In this article, we study estimation of a partially specified spatial panel data linear regres-sion with random-eff ects. Under the conditions of exogenous spatial weighting matrix and exogenous regressors, we give an instrumental variable estimation. Under certain su? cient assumptions, we show that the proposed estimator for the finite dimensional parameter is root-N consistent and asymptot-ically normally distributed and the proposed estimator for the unknown function is consistent and asymptotically distributed. Consistent estimators for the asymptotic variance-covariance matrices of both the parametric and unknown components are provided. The Monte Carlo simulation results verify our theory and suggest that the approach has some practical value.